1. Field of the Invention
This invention relates to data backup software for computer systems. More particularly, the invention relates to a system and method for creating a synthetic backup image on a remote host computer system coupled to a local host computer system, e.g., where the synthetic backup image is created from a full backup image and one or more incremental backup images received from the local host computer system.
2. Description of the Related Art
Computer systems often employ backup solutions to backup data in order to protect it against hardware failure or data corruption. Data may be stored on a storage device or in a logical volume of the computer system in the form of files. Backup techniques for backing up the files generally operate to create a backup image. One general backup technique is to backup the files at the file level, e.g., to include the files in the backup image on a file-by-file basis. In this technique, all the data for a given file is typically stored in the backup image, followed by all the data for the next file, etc. Another general backup technique is to backup the backup the files at the storage device block level rather than on a file-by-file basis. In this technique, the blocks may be sequentially read from the disk drive or other storage device on which the volume is stored and written to the backup image.
The backup image may be used to restore the data to the computer system in the event that it becomes necessary to do so, e.g., if the storage device on which the data is stored fails, if the data becomes corrupted, or if a user or software application needs to access the data is it existed at the time the backup image was created.
Some backup solutions operate to create different types of backup images, such as full backup images and incremental backup images. A full backup image includes all the data of the storage device or volume that is being backed up. Thus, a full backup is a complete representation of the storage device or volume data as it exists at the time the full backup is created. An incremental backup image includes only the data that has changed since a previous backup image was created.